In conventional electrical wiring applications, it is often necessary to conductively interconnect a number of electrical wires. Such a need would arise, for example, when a single "hot" wire must be branched off to a number of separate electrical outlets or lighting fixtures. So-called "wire-nuts" are traditionally used to connect a number of individual wires by twisting the bare ends of the wires together. Hosever, these wire nuts suffer a number of disadvantages, among them limitations as to the number of wires that can be interconnected. Furthermore, when several wires are connected by a single wire nut, if one wire pulls loose from the wire nut, the remaining wires are not wedged so tightly together and are more apt to pull loose also.
Accordingly, there is a need to provide a means for interconnecting a plurality of electrical wires which does not limit the number of wires which can be interconnected.
There is a further need to provide a means for interconnecting a plurality of electrical wires wherein a single wire can be disengaged from the connector without affecting the security with which the remaining wires are engaged by the connector.
Terminal blocks are known which permit easy insertion of the electrical wire but which resist the wire being pulled out of the terminal block. A widely used type of terminal block provides a plurality of wire-receiving guide passages into which the ends of electrical wires are inserted. The guide passages are electrically connected by an internal metal slip, and resilient leaf-spring wireretainers disposed at acute angles to the wire-insertion paths bias the inserted wires into contact with the metal strip. During insertion, the wire is simply pushed into position between the leafspring and the conductive element opposite the spring. By forming the leaf-spring members such that they incline toward the wire and extend along the wire in the direction of insertion, forming an acute angle to the wire, the edge of the leaf-spring at the end of each wire-engaging portion tends to dig into the wire to resist pull applied to the wire. This arrangement is such that very large pull forces are inherently resisted by the leaf-spring.
While such an arrangement affords ease of connecting the wires and resistance to accidental disengagement of the wires from the terminal block, it suffers certain disadvantages in that if it is desired to purposely disengage the electrical wire from the terminal block, disengagement cannot easily be accomplished. Specifically, the leaf-spring member resists pull applied to the wire so efficiently that the wire cannot be extracted from its guide passage and must be cut.
Accordingly, there is a need to provide a terminal block which affords ease of insertion and resistance to accidental disengagement of the electrical wire from the terminal block, but which permits the wire to be intentionally disengaged should the situation so require.